Views:126 Author:Site Editor Publish Time: 2017-02-08 Origin:Site
What Is Deep Hole Drilling?
A deep hole is defined by its depth to diameter ratio (D:d), typically greater than 10:1. Gun drilling is a precision process to drill deep holes in a variety of materials, from aluminum to super alloys. Good finish, tight diameter control and straight-ness are part of the finished process with deep hole drilling methods.
Deep hole drilling is beneficial across several applications. Oil and gas exploration equipment, armaments, aerospace equipment, and engines are common applications for deep hole drilling and machining processes. In each of these industries, hole qualities are necessary for high-performance end products, such as landing gear that easily retracts. Production requires deep hole drilling that is reliable, accurate, and time-efficient.
Advances in technology allow common CNC machining centers, equipped with high pressure through-spindle coolant, to be capable of gun drilling up to a certain depth-to-diameter ratio.
Deep Hole Drilling Tools
Small diameter drilling, typically 1 – 50mm [0.04 -2.00in] diameter holes
High-pressure coolant is introduced through the spindle and gundrill center
Chips are discharged on the outside of the tool
Special forms can be ground in tool tip
Larger diameter drilling, typically 20 – 200mm [0.79 - 8 inch]
Counter-boring and trepanning tools cover larger range, up to 500mm [20 inch] diameter
High-pressure coolant is introduced around the outside of the tool
Chips are discharged through the tool center and machine spindle
High penetration rates and power requirements compared to gundrill tooling
Deep Hole Machining
After drilling, additional machining methods can further improve deep hole concentricity, straightness, surface finish, and more. These methods machine the inside surface of the hole, much like other external machining processes, and most can be performed on a BTA deep hole drilling machine.
Processes are performed on a workpiece with an existing bore due to prior drilling or centrifugal casting, and an inside diameter surface exists. Many of these deep hole machining processes have been optimized for specific applications, such as skiving machines for the hydraulic cylinder industry, or bottle boring for landing gear actuators.
Deep Hole Drilling Applications
These example cases for deep hole drilling portray typical applications, processes, and tolerances achievable with proper tooling and equipment. Applications for deep hole drilling exist across nearly all manufacturing sectors, with new applications emerging regularly.
The high depth-to-diameter ratio holes in these applications show extreme tolerances of straightness, roundness, concentricity, surface finish, etc.
Our customers have come to rely on their high volume deep hole KONETOOL drilling blanks to accurately predict production levels and costs without making concessions for unnecessary downtime. This dedication to accuracy and reliability is at the heart of every high volume deep hole drilling machine.
Fuel Rails for Diesel Engines - Drill holes at extreme depth-to-diameter ratios in long workpieces without sacrificing accuracy in roundness or wall thickness.
Operation - Gun drilling
Aerospace industry requires highly accurate deep hole drilling of exotic materials. High temperature materials such as Inconels and Titanium alloys are commonly seen along with some specific heat treated Steels and Aluminums. KONETOOL provides gundrill blank tips for drilling precision deep holes into engine components, landing gear components etc.
Aircraft Landing Gear - Drill and contour landing gear actuating cylinders while holding an extreme straightness tolerance in high-strength alloys.
Operation - BTA solid drill, Bottom contour forming, Center pressure hole drill
Oil And Gas Exploration
Throughout its history, supplier has been meeting the demanding requirements in the Oil and Gas exploration tooling and provides solutions for both on-center and off-center deep hole drilling of high value workpieces that meet demanding tolerances.
Oil Field Exploration - Drill holes at extreme depth-to-diameter ratios in long workpieces without sacrificing accuracy in roundness or wall thickness.
Operation - Pull boring with boring bar in tension, roller burnishing for surface conditioning
Large turbine shafts and heat exchanger parts are key areas of the energy industry where BTA tooling have played an important part in meeting increasing global demands.
Multipurpose boring and turning machines for the production of large turbine rotors, generator shafts and wind mill shafts continues to be a growing portion of deep hole engineering and production resources.
The applications engineering experience gathered from drilling of large diameter shafts has been successfully adapted to small diameter BTA drilling of Inconel-clad tube sheets used in heat exchanger production. The column style multi-spindle machines are specifically designed for tube sheet drilling applications. These machines have dramatically reduced processing times, enabling customers to compete in the global heat exchanger market.
Heat Exchanger Tube Sheet - Thousands of accurate holes are achievable quickly and efficiently on a multi-spindle tube sheet drilling machine.
Operation - BTA Solid Drilling on multiple spindles, 2160 holes per part